Better Bridges: Bridge Inventory 2009 State of Bridges

The Better Roads Bridge Inventory is an exclusive, award-winning annual survey that has been conducted since 1979. Bridge engineers from every state and Washington, D.C., are set a survey with both qualitative and quantitative questions. The Federal Highway Administration, in consultation with the states, has assigned a sufficiency rating, or SR, to each bridge (20 feet or more) that is inventoried. Formula SR rating factors are as outlined in the current Recording and Coding Guide for Structures Inventory and Appraisal SI&A of the Nation’s Bridges. The qualitative data is gathered through a questionnaire about major issues concerning bridge conditionsand maintenance.

Shockingly high number of bridges remain sub-standard.

There are 597,787 bridges in America, 288,920 interstate and state bridges and 308,867 city/county/township bridges.

But 21.6 percent – or 62,504 – of the interstate and state bridges are structurally deficient (SD) or functionally obsolete (FO). And 25.7 percent of the city/county/township bridges – or 79,394 – are SD/FO.

Texas leads the nation with the most combined structurally deficient and functionally obsolete bridges. The state has 9,564 — 19 percent — of its total 50,316 bridges as SD/FO. Of the total 32,862 interstate and state bridges, 4,182, or 31 percent, are SD/FO. Of the 17,454 total city/county/township bridges, 5,383 or 13 percent are SD/FO.

Pennsylvania is second with 9,130 of its total 23,562 bridges, or 39 percent, as SD/FO. The state has 16,668 total interstate and state bridges, with 5,971 — 36 percent — reported as SD/FO. Forty-six percent, or 3,159 of all the state’s 6,875 city/county/township bridges are considered SD/FO.State officials note that funding is the greatest challenge to lowering the state’s rate of bridge deterioration, but corrosion, heavy salt use and more traffic than bridges were designed to carry cause the greatest damage.

But, Lance Savant, P.E., with Pennsylvania Department of Transportation’s Bureau of Design, says his state expects to be able to lower its rate of its structurally deficient and functionally obsolete in the coming year. “Pennsylvania has its accelerated bridge program which focuses on replacing/repairing SD bridges,” Savant says. Nonetheless, bridges could certainly be improved if the state could “devote more funds to bridge preservation…to keep the good bridges good,” he says. Many of the other states’ agencies echo the same sentiment.

Following Pennsylvania, in order,the other top five states with the highest number of combined total SD/FO bridges are Missouri, Ohio, and Oklahoma.

Missouri has 24,096 total bridges, a combined total of 7,103, or 29 percent, which are SD/FO. There are 10,249 total interstate and state bridges, 2,838, or 28 percent, of which are SD/FO. Of the 13,847 total city/county/township bridges, 4,265, or 31 percent are SD/FO.

Ohio has 6,993 — 23 percent — of the total 30,617 in the state being SD/FO. Of the total 11,639 interstate and state bridges, 2,475, or 21 percent, are SD/FO. Of the total 18,978 city/county/township bridges, 4,518, or 24 percent, are SD/FO.

Finally, 6,904, or 29 percent, of Oklahoma’s 23,646 total bridges are SD/FO. Of its 7,660 total interstate and state bridges, 1,639, or 21 percent, are SD/FO. Thirty-three percent, or 5,265, of the state’s 15,986 total city/county/township bridges are SD/FO.

Like Pennsylvania, Oklahoma also expects to be able to lower its number of SD/FO bridges within the coming year. Bob Rusch, bridge division engineer for the Oklahoma Department of Transportation, says this is the fourth consecutive year the number of bridge projects in the state’s eight-year Construction Work Plan has increased and represents the largest increase in bridge work ever incorporated into the plan.

“The department’s Federal Fiscal Years 2010 -2017 Construction Work Plan enumerates priorities for highway and bridge construction during the next eight years and includes more than $4 billion in improvements to the state’s bridges and highways,” Rusch says. “The plan continues the agency’s focus on bridges with an increase of more than 100 bridges over last year’s plan for a total of more than 560.” In addition, he adds, “The department is also continuing to make strides in our State Bridge rehabilitation Program which provides significant repairs to existing bridges.”

The actual number of bridges doesn’t always paint the most accurate picture of deficiency or obsolesence. A state with fewer bridges could have a higher percentage of bridges that are SD/FO, but the numbers of SD/FO bridges could actually be relatively low.

The highest percentage of SD/FO bridges in the nation – 55percent – is in the District of Columbia. By percentage, Rhode Island** comes in second with 53 percent SD/FO bridges, followed by Pennsylvania at 39 percent, Hawaii at 38 percent and New York at 37 percent.

Regardless of what the official statistics show about the number of bridges that are SD and FO, some bridge engineers say that we should look at the square footage of SD and FO bridges to get a true picture of the situation. Ray Mumphrey, highway bridge program manager with the Louisiana Department of Transportation, says that while the number of SD/FO bridges may have decreased, the square footage may actually be increasing. “It may look like we’re making progress [in the nation] with the number of deficient bridges, however larger bridges are becoming deficient which increases the square footage of deficient bridges,” Mumphrey says. “There are a lot of interstate [bridges] becoming deficient, although the numbers of deficient structures may have gone down.”

Adds John Jones, M.S., P.E., Bridge Manuals, Modeling and Policy Engineer with the Kansas Department of Transportation (KDOT): “In all cases, square footage is the best indicator of [their] status.”

Clearance and capacity concerns

Even after the August 2007 collapse of I-35W Mississippi River Bridge in Minnesota, bridge needs are still not being seen as “critical,” says Dan Holderman, P.E., a bridge management engineer with the North Carolina Department of Transportation. “Even after the I-35W collapse, [there is still] very little emphasis on bridges and other infrastructure.”

Investigators found that the Minneapolis bridge, which killed 13 people when it collapsed into the Mississippi River failed because of a flaw in its design, when it announced its findings on Jan. 14, 2008. The designers had specified a metal plate that was too thin to serve as a junction of several girders, investigators say, according to a New York Times report immediately following the findings.

The bridge, which was designed in the 1960s, lasted 40 years. However, like most other bridges, the Times reported, it gradually gained weight during that period, as workers installed concrete structures to separate eastbound and westbound lanes and made other changes, adding strain to the weak spot.

This is when the bridge problem becomes more than a structural issue. It also becomes a capacity and a clearance issue. Although bridges can be functionally obsolete (e.g. geometrically deficiencies such as waterway openings, width, clearance issues, etc.) they are still considered safe to the motoring public even if they aren’t up to the standards – such as the current-day recommended width – for modern-day standards and commerce.

“We have so many oversize and overweight vehicles that go through Indiana, [and] we have to route vehicles all over the place because of structurally deficient, low-capacity or low-clearance bridges,” said Bill Dittrich, state bridge inspection engineer for the Indiana Department of Transportation. “In the early to mid 1980s, we [the state of Indiana] didn’t allow permitted vehicles on our interstate highways. Now, we are letting trucks go over them.”

Mike Clements, Georgia Department of Transportation state bridge engineer, says that’s part of the problem in his state, too. “Increased weight limits” is Georgia’s major cause of bridge damage, he says.

Because structurally deficient bridges can also be a safety concern to the public, Indiana DOT’s Dittrich says, highway agencies, the media and political people have keyed in on that term, “structurally deficient.” But that is not where the money is being spent. “We’re spending a ton of money on adding capacity, but not addressing structurally deficient the way we should. Many of our existing bridges are reaching the point where they are now becoming structurally deficient.,” he says.

Bridges can be neglected for a while and their condition won’t change a great deal. But all of a sudden, Dittrich says, “there will be a whole lot of structurally deficient bridges and there just isn’t the money to address them all at once.”

The training and retention predicament

Training and retention is a major concern when it comes to bridge inspection and repair. It’s no secret that the construction industry faces a shortage of qualified workers, and it carries over into bridge repair and inspection. “Bridge inspectors aren’t given the respect they should be,” Dittrich says, adding that a mindset exists that “anyone can do the work.” But it’s to the contrary. “The qualifications keep increasing,” Dittrich says, “and you need training.” He likens it to an untrained paramedic showing up to an emergency scene. “You don’t want to have a guy to show up in an ambulance who hasn’t had CPR training in 10 years,” Dittrich notes. “Half of my inspectors aren’t engineers, but they are expected to know things an engineer would know…and we don’t have adequate funds for training and travel to training. If I can’t keep them up to date, how can they be expected to see the problems they need to see? Or, they may see them [problems] but not understand what is significant and what isn’t.”

The growth of virtual training tool such as Webinars has helped somewhat with the lack of funds for training. However, when there are a limited number of inspectors this training takes time away from fieldwork regardless whether it’s on a computer or in person traveling to a training site. Dittrich points out that one of his inspectors just completed a Webinar on gusset plates but that employee said he ended up working for what seemed like 24 hours if he counted in virtual training and completing paperwork on bridge inspection reports. “You can inspect all you want, but it doesn’t do any good if you don’t have enough personnel or enough funding to address the problems that are found,” Dittrich said. There is enough work to keep his inspectors busy all the time, he says, but it’s still a major problem if they aren’t properly trained or if there aren’t enough of them to get the job done and done well. “Not having enough personnel is our No. 1 problem. The work keeps increasing therefore everyone has to do more.”

Though Congress and the Federal Highway Administration (FHWA) approved funds in the last highway bill — SAFETEA-LU — that were to be used for training and development and would cover travel, per diem, etc., the money ultimately comes off the top of the money a state gets for its bridge program, Dittrich says. “We’re caught in a situation. The federal government and Congress said, ‘We made money available,’ but the states need money for construction. That means we don’t have money to give to the guys for training. I think every state has this kind of issue. The regular money we get, we use the best we can. But we aren’t necessarily being effective with getting the structurally deficient bridges taken care of.”

Dittrich says to address the need for better training, his state inspectors have peer group meetings 4 to 6 times a year. Bridge inspectors from throughout the state get together to talk about ideas, inspection and repair methods that have and have not worked, creating a forum to share knowledge.

“Nothing frustrates a bridge inspector more than to see something that’s fixed and have it fail again in five years,” Dittrich says. “If you put a new deck down and it’s not cured properly, then it cracks, salt gets in, and it deteriorates. But decks and concrete can be made and cured right. It all starts with the mix and rebar…knowing where to stop the rebar.”

This is where the training comes in, Dittrich points out, because it can mean the difference between a bridge that lasts and a bridge that falls into disrepair before its time. “If you jackhammer off all the bad concrete, , you still have good with chlorides in it,” he points out. “You’ll have new concrete with no chlorides next to old concrete with chlorides. This difference in chloride concentration will set up a battery cell which will accelerate the corrosion of the rebars in the vicinity. Therefore testing should be conducted prior to making repairs to see if the choride levels are low enough to use zinc anodes, or if more advanced cathodic protection is required.

“That means you need to have a corrosion specialist go through it,” Dittrich points out. “But this is all new stuff — it’s not done on a widespread basis. We’d love to have our maintenance people be able to do this when they make a patch because they fix an area…when they come back a year later, it’s worse than ever. It all comes back to training, so when they start [on a project], they [know how to] do it right so it will last.”

Environmental challenges

Environmental restrictions continue to affect how well states and municipalities can replace and repair deficient bridges. These restrictions often slow down the process of repairing and replacing bridges, and sometimes, a less-appropriate structure type is used to replace the bridge, KDOT’s Jones notes. This just exacerbates the problem of structurally deficient bridges because more appropriate materials that would keep a bridge in better condition longer are not used.

“When a small span structure can efficiently be replaced with a standard box culvert, the environmental regulatory agencies providing oversight feel that culvert floor is considered ‘loss of stream length’ and has to be mitigated,” Jones points out. “Also, if there are threatened or endangered species present or perceived to be present, that also has to be mitigated.”

The process for reviewing this is complicated by the wide variations in what is considered “acceptable,” even to the point that it depends on who in the various agencies is conducting the review, he says.

“Additionally, we must develop a full set of plans, then send it in and wait,” Jones says. “The process is difficult, time consuming and expensive. The frustrating part is [that] some of the reviewers do not understand the bridge engineering principles involved. And some of solutions are not hydraulically feasible.”

Time constraints are also a major roadblock to repairing and rebuilding the bridges that need the most work, says Dittrich.

“When it came to using ARRA Funds, often the the bridges that needed the most work, weren’t the ones worked on,” Dittrich says. “I had a number of bridges that we proposed in the early part of the ARRA Program that we wanted to work on and do them right.” But as time progressed, he says, the deadlines were getting closer and closer so although the agency had money to spend, functionally obsolete or structurally deficient bridges weren’t the ones necessarily worked on. Basic maintenance was done to some of the bridges, but Dittrich says his agency will have to go back and do additional work on those where we couldn’t take care of all the problems. “To increase the vertical clearance under bridge to address the obsolescence can take a while unless a project is ready to go,” Dittrich notes.

And the time to finish a project once it does get underway is problematic. For example, he says, when it’s time to do a concrete pour, “instead of slowing down to do it right, as soon as concrete trucks get out there [on the jobsite], people just rush, rush, rush. Everyone is in a hurry.”

Richard Dunne, P.E., manager of structural engineering for the New Jersey Department of Transportation (NJDOT), also feels the time crunch. He says if he could change any aspect of his department to improve the bridges under its jurisdiction, it would be “[a] willing[ness] to inconvenience motorists more.” Currently, Dunne says, “we do the majority of our work at night and/or in very small time windows.”

The Kansas Department of Transportation also identifies with this challenge. “It seems like no one wants to take the heat for detouring traffic, so we end up carrying traffic through construction, which requires the work to be phased,” says KDOT’s John Jones. “In some instances — like a rail repair — this is less of an issue. However, for deck repair or replacement, this becomes challenging.” v

Even with the American Reinvestment and Recovery Act (ARRA), better known as the stimulus, funding availability is still one of the biggest challenges in lowering the number of states’ deficient bridges, say respondents to the Better Roads survey. From The Midwest to the South to the Southeast to South Dakota and even as far-flung as Hawaii and Washington, D.C, agency officials still rank funding availability as one of the greatest challenges to repairing derelict bridges.

However, ARRA has provided some relief and has increased the level of funding for bridges. It has enabled maintenance and reconstruction of some bridges that would otherwise not be possible. The results of ARRA spending range from having no effect or a minimal effect to modest or significant impact. These responses are not unfamiliar to highway transportation official assessing the impact of the stimulus. Anwar Ahmad, assistant bridge engineer for the Virginia Department of Transportation, tells Better Roads that the stimulus “was a much-needed booster for our bridge program.”

David Koenig, bridge structural service engineer with the Missouri Highway and Transportation Department, agrees, noting that the ARRA has had a very positive, “large impact” on Missouri’s bridge projects. “Many bridge projects have been moved up in the schedule and more have been addressed,” he says.

Minnesota has benefited from stimulus money. “Over 50 bridges on Minnesota’s state and local highways have been advanced with ARRA funding,” says Tom C. Styrbicki, P.E., bridge construction and maintenance engineer, Minnesota Department of Transportation Bridge Office. “The projects include everything from minor repairs to full bridge replacements. The ARRA program was a particular benefit to bridges in the local system.”

Steve Anderson, Nebraska Department of Roads, Bridge Divisions, says the stimulus “has accelerated a few projects [at the] state and local level.”

Division, Washington, D.C., also notes that “the ARRA has increased the level of funding for bridges” in The District.

Chris Potter, Utah Department of Transportation, Bridge Design & Operations, says his state is using the money to replace several structurally deficient bridges and bridge decks. “In addition, we are using it to apply preservation treatment to several bridges,” he says.

A temporary funding frenzy

Kent Barnes, Montana Department of Highways, Chief Bridge Bureau, says that although the ARRA helped to fund a few additional short-span bridges, for the most part, it had a “low impact on the bridge program.”

Paul Santo, bridge design engineer, Hawaii Department of Transportation, says the stimulus also has “assisted in funding a couple of bridge projects, [but] it has not made a significant difference.” Benjamin W. Foster, assistant bridge maintenance engineer, Maine Department of Transportation, says in his state, “a modest amount” of money was used for bridges.

Kansas DOT’s John Jones says some bridges were “let” that otherwise would not have been, but “we’re still waiting on next year’s distribution.” Essentially, he says, some projects that were financially marginal became feasible. The same was true for Texas. Alan Kowalik, P.E., bridge inspection engineer for the Texas State Department of Transportation, says that bridges that were on the state’s “Five-Year List” were moved up to be replaced and repaired.

What major overhauls are needed to the systems of planning, building and maintaining bridges in the United States at the federal, state and local level? Why?

Anwar Ahmad, assistant bridge engineer with the Virginia Department of Transportation: “Adoption of a national ‘maintenance and preservation first’ policy supported by a reliable and sustained funding mechanism. Focusing on deficient bridges alone will lead bridge owners to focus on addressing or reacting to worst-condition first [bridges]. A successful bridge program should have three focus areas: 1.) Ordinary and preventive maintenance, 2.) Rehabilitation, and 3.) Replacement and new construction. In most cases, the most feasible treatment for a deficient bridge is replacement. The same or higher emphasis needs to be placed on preservation as placed on replacement and new construction activities and needs.”

If you could change any aspect of your department to improve your bridges, what would it be?

Noel Clocksin, secondary road engineer for the South Dakota Department of Transportation: “A more streamlined federal aid process and state process for local structure so we can get deficient structures replaced more quickly.”

Alan Kowalik, P.E., bridge inspection engineer for the Texas State Department of Transportation: “More bridge maintenance to keep them from becoming ’50.”

Dan Holderman, P.E., bridge management engineer with the North Carolina Department of Transportation: “Bridge funding [because] more bridges become deficient each year than are removed from the list, [and a] larger dedicated bridge maintenance fund.”